How are frequencies sorted in frequency response?

[bjorn_fallqvist]

Since I have problems with my frequency response, in the results environment, the actual frequency does not show (it just says "Frequency: not available"). I thought this was because I terminated the analysis_server application (after 18 hours of "writing results to stress output files and superview"!), but then I ran a tutorial (the truss tower, still available on www.algor.com), and the same thing happens there, even though the analysis completes as it should (see screenshot).

How can I know which load case corresponds to which frequency? And how are the natural frequencies (which were included) sorted? Are they put in their "right places" between the defined exciting frequencies? Ascending order? Descending? All first? All last?

Please help me out here.

Thanks

[xli · Accepted solution]

Hi, Bjorn,

"writing results to stress output files and superview" is a stress recoverying proceesor's message. If your model is really huge and you select large frequencies in modal analysis to conduct your frequency response analysis, that 18 hour long MIGHT be explained. Hmm.... if you also saw 18 hours outputting stress results on that small tutorial model, it is really odd.

modal analysis alweays gives out natural frequencies in ascending order as well as associated mode shapes. Most LD analysis do not have option to re-sort the frequency order, except DDAM. The corrsponding load case is NF + 1...., i.e. resultant responses are agfer NF natural frequency responses.

Hope this explain your question a litttle bit.

-xli

[bjorn_fallqvist]

Hi,

I meant that I also get the "Frequency: Not available" problem in small tutorial models also. But maybe it's supposed to be like that?

It answers my question. Thanks.